Many types of milling machines are known, employing brush mills, to roughen suitably the edges of vamps folded under the shoe sole; some types employ a couple of rotating brush mills, which can be applied transversely to the two opposite longitudinal edges of the vamp, and between them the vamp on the shoe last is transported. These types of machines are not always suitable to produce the roughness on the toe and on the heel, so that after the working on the machine, the shoe must be submitted to further finishing operations.
Other, more recent and complex machines employ a single brush mill, mounted on supports which can move transversely to the shoe to be worked, and controlled by copying mechanisms following the shape of the shoe being worked; with these solutions, the shoe is held by supports which can move axially in both directions and swivel on a horizontal plate in such a way as to offer to the action of the mill both the opposite peripheral edges and the curved sections of the toe and the heel.
In general, all the known machines have disadvantages and limitations of use: as matter of fact often the roughness is not uniformly distributed along the whole peripheral edge especially when the folded edge is creased, and when the skin is particularly delicate. Furthermore, these machines are affected by limitations in the depth (width) of the milled zone and in the constancy of such width, and they do not allow variations of the width of the roughened zone, if necessary, in particular parts of the shoe, because the copying mechanisms which guide the mill follow the shoe last on which the shoe vamp is fitted, without possibility of varying, if necessary, the depth or width of certain critical zones of the vamp edge.
It is therefore an objective of the present invention to realize a machine of the aforementioned type, improved to overcome the disadvantages and limitations of the known milling machines, and in particular, a machine fitted with devices and mechanisms improved in such a way as to obtain peripheral edges of uniform roughness and wanted width, whatever is the size of the shoe, its shape and the type of skin of the vamp.
Another objective of the invention is to realize a milling machine operating in a completely automatic fashion, and offering constancy and regularity of working such as to exclude any successive manual finishing operation.
Such objectives are profitably obtained by a milling machine for the roughening of the edges of a shoe vamp folded under the sole of the shoe, employing a brush mill, driven by its own electric motor and mounted on a swinging counterweighted arm, such machine comprising, according to the invention: a base plate on which is fitted up a first vertical column carrying a horizontal swiveling arm to whose extremity a movable and horizontally displaceable plate is hinged; a shoe carrying unit being able to rotate, on said plate, and movable with it, and consisting of adjustable supports for the holding and fastening of the shoe in upside down position, and of couples of clamping lugs for sideway clamping of the shoe, constituted by rods which can be moved apart by hydraulic cylinders fixed to said plate; said machine comprising a second upright supporting a curved arm rotating in a horizontal plane, fitted at one extremity with a bracket supporting the oscillating arm of said brush mill with relative motor and counterweight, such arm being coupled to two hydraulic cylinders one of which creates the necessary pressure of the brush on the edge of the shoe and the other controls at the start the approaching of the arm and gives the signal for starting the movement of the shoe carrying unit; a rod shaped feeler, with horizontal axis, hinged on said bracket carrying the brush-counterweight-motor unit, and in contact with two templates one with the profile of a right shoe and the other with the profile of a left shoe, placed on the same axis of the shoe carrying unit and connected to the movable plate supporting the same shoe-carrying unit, by means of a frontal coupling, which can be opened by a hydraulic cylinder suitable to raise said movable plate and the shoe carrying unit to allow for the substitution of the templates; a hydraulic cylinder acting on said brush carrying arm, and suitable to keep constantly the said feeler in contact with the said templates, during the milling, thereby allowing the rotating brush to follow the profile of the shoe; a carriage movable in the two directions parallel to the longitudinal axis of the shoe, by means of a horizontal hydraulic cylinder which can displace said movable plate and the relative shoe carrying unit, so as to keep the edge of the shoe always in contact with said brush mill; a plate fixed to said carriage controlling hydraulic cylinder, rotating on a vertical axis by means of a hydraulic motor with relative transmission and reduction gears, capable of rotating of 180.degree. the carriage, the template and shoe carrying units, at the end of each movement of the carriage in the two directions, thus allowing the brush to roughen the curved edge of the toe and heel respectively, provision being made for a decelerating valve with a cam associated to said gears driven by the hydraulic motor, in order to obtain the automatic stopping of the rotating plate, at the end of the 180.degree. rotation, and provision being also made for a hydraulic rotating distributor, on the same axis of the rotating plate, for supplying fluid in pressure to the various hydraulic cylinders of the machine.
More in particular, said feeler can be reduced in length by means of a hydraulic cylinder, in order to allow a greater feed of the rotating brush towards the central zone of the shoe thereby obtaining, through two complete revolutions of the revolving plate, two millings, an inner and a peripheral one, on the same shoe. Furthermore, in order to have a constant sharpening and cleaning action on the rotating brush, on the support of the oscillating, counterweighted arm of the brush, a grindwheel actuated by its own motor is mounted, which can be raised and brought close to the same brush, by means of a hydraulic cylinder.